A great deal of social psychological research has focused on antecedents of conformity to the majority. The present article, however, reviews the various conditions under which people express minority opinions. First, minority opinion expression is especially pronounced among individuals who hold either strong attitudes or attitudes that deviate from the majority in a direction consistent with the desirable group attitude. Second, minority opinion expression increases to the extent that highly-identified group members believe that expressing minority opinions will promote their group’s welfare, or to the extent that one’s membership in a particular social category entitles him/her to speak up. Third, minority opinion expression increases when people’s motives to have a unique or clearly defined sense of self are salient. It is argued that these sources of minority opinion expression can help shed light on the functional value of such opinions for individuals.